16 · Head style · drive access on print
Socket head cap screw vs hex head bolt on RFQ drawings
On stone cladding brackets, structural splices, and heavy baseplate joints, a vague “bolt / screw” line without head style forces dual quotes. Socket head cap screws (Allen / hex-socket drive) and hex head bolts need different wrench clearance, counterbore, and washer rules. This desk locks which head the controlling revision owns — plus drive access notes — before any unit price is useful. Dashitou does not publish brand charts, torque tables, or “universal head” swaps here.
Define · what this RFQ is for
Use this desk when overseas buyers quote Dashitou stone · structural · heavy fasteners and the print must choose a head style — socket head cap screw vs hex head bolt — for drive access, counterbore, or under-head bearing. You own joint design and engineer sign-off; we confirm which head appears on the revision, diameter × length, grade / finish lock, and qty band against that revision.
Pair with flange bolts vs hex head (G12) when flange vs plain hex is still open, structural bolt class & coating (G8) when class/finish sit with the head callout, thread engagement vs grip (G11) when stack-up drives length under a counterbore, torque vs preload vs proof load (G13) when clamp figures sit beside the head, cladding bracket slot vs hole (G5) when hole type changes bearing, and drawing handoff for revision lock. Then open Enquire / RFQ.
Discuss · fields that change the quote
Each row below is a desk check. Missing rows stay Open — we do not invent socket brands, hex family swaps, or “Allen OK anywhere” rules on this public page.
Field desk · 01–06
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Head style (socket head vs hex head) Name socket head cap screw (hex-socket / Allen drive) vs hex head bolt (external hex). “Bolt / screw” alone invites dual quotes. Prefer the print’s named head or mark Open with a preference rule.
- Email example: Socket head cap screw · hex head forbidden in counterbore (Rev C)
- If missing: Open — do not assume hex from a catalog photo
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Drive access / counterbore note Socket heads need hex-key / bit clearance; hex heads need wrench swing or socket clearance. Counterbored pockets often force socket head. Write the access note when the revision owns it; otherwise mark Open with a preference.
- Email example: Counterbore pocket · socket head only · hex wrench swing N/A
- If Open: mark preference on the print or RFQ notes
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Under-head bearing / washer rule Socket heads usually seat on a cylindrical under-head; hex heads often pair with a flat washer. Soft cladding faces or isolation pads may still need a washer rule even with socket — write it. Separate from flange-head choices — see G12.
- Email example: Hex head + flat washer under head; socket zone no washer (Rev C)
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Diameter × length & grip / engagement Lock diameter × length with grip/engagement and whether a washer sits under the head or nut. Counterbore depth can steal length from engagement — write stack notes explicitly — see G11.
- Email example: M12 × 50 socket head; counterbore 13 deep · engagement per print
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Qty band & destination Mock-up joint set vs project lot; destination for packing notes. Discussion band is enough for the first reply.
- Email example: Qty band: mock-up 120 pcs → project lot TBD · dest EU
What must appear on the print
- Head style named (socket head cap screw vs hex head bolt)
- Drive access / counterbore note when clearance drives the choice
- Under-head washer rule when bearing or isolation owns it
- Grade / finish lock with the mating nut — see A2 vs A4 coastal · structural class
- Controlling revision — see drawing handoff
Agree · before we number
Until the following are aligned, treat any figure as discussion only:
- Controlling revision locks socket head vs hex head (or marks Open with a preference)
- No invented “Allen OK for all hex” swaps or site wrench-clearance tables posted as policy here
- Flange vs plain hex (G12), class/coating (G8), and engagement (G11) notes settled or linked in the same thread when those desks apply
- Samples and private-label marking only after head style, access notes, and diameter × length are clear
We do not invent certificates, plant area, or ranking badges here. Project documents that matter to the RFQ are shared privately when relevant.
FAQ · socket head vs hex head bolt
Is “bolt” or “screw” on the BOM enough to quote socket or hex head?
Usually no. Socket head cap screws and hex head bolts are different head / drive conditions. Name the head style on the controlling revision, or mark Open with a preference rule. Vague “bolt / screw” language often forces a resubmit.
When should an RFQ lock socket head instead of hex head?
When counterbore pockets, limited wrench swing, or engineer rules require hex-socket drive access. Do not swap hex head to socket on this public desk without the print. Write the access / counterbore note beside the callout.
Does choosing socket head replace naming washers or flange head?
No. Socket vs hex is a head / drive choice. Under-head washers, isolation pads, and flange vs plain hex remain separate lines — see the flange vs hex desk when that choice is still open. Treat them independently on the RFQ and the print.
Can one RFQ mix socket-head and hex-head zones?
Yes, when zones are explicit on the BOM (for example socket in counterbored cladding brackets, hex head on heavy baseplates). Ambiguous “socket/hex OK” without zone ownership often splits the quote. Lock zones or mark Open with a preference rule.
What should I send so Dashitou can review the head-style line cleanly?
Open Enquire / RFQ, then email the PDF/STEP or marked sketch to shizhanhao6@gmail.com in one thread. Include head style, access/counterbore notes if relevant, washer rule if relevant, A2/A4 or class/finish if relevant, diameter × length, qty band, and destination. Skim G8, G11, and G12 when those desks apply. No cart; no list prices on this site.
Next step
Skim flange vs hex RFQ · structural bolt RFQ · engagement vs grip RFQ · RFQ checklist, then open Enquire / RFQ. Direct email: shizhanhao6@gmail.com.